Presently, component libraries for building layouts of printed circuit boards are established according to data from component manufacturers. When establishing a library, it only needs to establish sizes of the entities of the padstacks, pins and components. However, some components may have two outlet directions, and actually only one outlet direction may have no effect on signal quality, the other direction may have effect on the signal quality. If there happens to select an outlet that has effect on a signal, the quality of the signal of the printed circuit board may be bad, and the quality of a product may be decreased.
FIG. 1 shows a layout diagram for a printed circuit board. As shown in FIG. 1, a layout area includes at least one padstack 1. A welding material area 2 is included on the padstack. The welding material area 2 is configured to be welded together with an element to be connected, such as an IC (not shown) and the like. Beside the welding material area 2 on the padstack 1, there also provides a blank area 3 on the padstack 1 that is not covered by the welding material area 2. A wiring needs to be connected with the padstack 1 of FIG. 1, so as to connect the element to be connected with other elements. A reference number 8 in FIG. 1 represents a framed layout area which is a part of the entire printed circuit board. For the convenience of description, other parts of the circuit board and other elements on the circuit board are not shown.
The element to be connected in FIG. 1 is welded together with the welding material area 2, and then is lead out through the wiring and connected with other elements, so that the layout in FIG. 1 has two outlet manners.
FIG. 2 shows the first outlet manner. FIG. 3 is a diagram that explains FIG. 2 in details. As shown in FIG. 2, the wiring 4 is connected with one side of the padstack 1 where the welding material area 2 is located. The element to be connected is welded on the welding material area 2. The element to be connected is not shown in FIG. 2. In FIG. 3, the element to be connected is represented by a reference number 6. As shown in FIG. 3, a pin 7 on the element to be connected 6, such as an IC, is connected together with the welding material area 2 on the padstack 1, and the wiring 4 is connected together with the welding material area 2, and then extends outwards to be connected with other elements. In the outlet manners as shown in FIG. 2 and FIG. 3, the wiring 4 does not pass through a blank area 3 on the padstack 1 that is not covered by the welding material area 2.
FIG. 4 shows the second outlet manner. FIG. 5 is a diagram that explains FIG. 4 in details. As shown in FIG. 4 and FIG. 5, the wiring 4 is connected together with the welding material area 2 through the blank area 3 on the padstack 1 that is not covered by the welding material area 2, and then is connected with the pin 7 of the element to be connected 6 which is welded on the welding material area 2. In this connection manner, the blank area 3 on the padstack 1 that is not covered by the welding material area 2 is covered by the wiring 4.
In the first outlet manner, the blank area 3 on the padstack 1 that is not covered by the welding material area 2 is reserved, and the blank area 3 on the padstack 1 is not covered by the wiring 4, which is equivalent to leave a small section of blank padstack. This section of blank padstack is a sharp bulge, which is equivalent to an antenna, so it is easy to induce or radiate high frequency signals, such that it may cause bad effects on the quality of signals of the circuit, so as to influence transmission stability of the signals. While the second manner avoids a circumstance that a part of the padstack 1 is left as a blank area since the wiring 4 is also welded on the blank area 3 on the padstack 1 that is not covered by the welding material area 2, such that the padstack 1 does not have a sharp bulge like an antenna, and may not induce or radiate high frequency signals, and thus may not influence the quality of signals of the circuit.
However, both the above two outlet manners may occur in practical applications, and it may not be determined which manner is adopted before outlet, thus there is a possibility of causing bad signal quality of the circuit.